Transient Stability Analysis and Stable Forms of the Grid-Connected VSC System with Limiter

The limiter is extensively configured in the renewable energy conversion system, which is mainly used to limit the current or avoid a large deviation of fault trajectory from the rating value. However, existing studies have not fully revealed the key parameters of the transient stability of the renewable energy conversion system with the limiters and instability pattern. To fill the gap, a grid-connected VSC system including the current limiter and frequency limiter is first established in this paper. Secondly, the influence of key factors on the transient stability of grid-connected VSC systems with limiters is investigated to conclude the stability forms. The results show that there is no monotonous tendency of influence between transient stability characteristics and key factors, which is significantly different from the results of ignoring limiters. Additionally, due to the limiter, two new stable forms appear, that is, the power oscillation of the peak clipping and the stabilization at the new stable equilibrium point caused by the switch between the control modes. The relevant work in this paper provides a reference to understand the stable features and dynamic behaviors of the renewable energy conversion system.